1. Technical Field
The present invention relates to a severing machine for cutting rolls or logs of great length into a plurality of small rolls intended for final consumption, or for cutting other elongate products, especially of weblike material, for example packs of paper napkins or other interleaved articles.
Machines of this type are commonly used in the paper converting industry for the production of rolls of toilet paper, rolls of kitchen paper and the like, or other paper articles.
2. State of the Art
In the paper converting industry, and especially in the production of products comprising tissue paper, provision is commonly made for the weblike material to be wound up into logs or rolls of large axial dimensions and diameter equal to the diameter of the finished article. These logs or rolls are subsequently cut into a plurality of small rolls, of axial dimensions equal to the final dimension of the article intended for consumption, by means of severing machines.
Typically, in order to perform the cutting of the rolls, use is made of severing machines which possess an assembly rotating or oscillating about a shaft and on which are mounted one or more disk-shaped blades rotating about their respective axes. The movement of the assembly brings the disk-shaped blade(s) mounted thereon to penetrate cyclically into the material forming the roll, which is caused to advance below the rotating assembly. At each cycle of the rotating assembly, at least one small roll is cut from one of the rolls being fed. Normally, a plurality of rolls are caused to advance in parallel and are cut simultaneously with successive passages of the same disk-shaped blade carried by the rotating or oscillating assembly. When the assembly carries two blades, two cuts are made during each cycle.
An example of a severing machine of this type is described in U.S. Pat. No. 5,522,292.
According to another known technology, provision is made to cut each roll into the final number of small rolls in a single pass by means of a series of parallel cutting blades. A severing machine of this type is described in U.S. Pat. No. 4,329,895. In this machine, the rolls to be cut are inserted into cradles which advance in a linear manner below a plurality of parallel rectilinear blades inclined relative to the direction of advance of the rolls. The blades all penetrate together and gradually into the material of the roll, cutting the latter into a series of small rolls during a single pass.
Another example of a severing machine which allows the simultaneous cutting of each roll into a plurality of small rolls is described in IT-B-1 103 635. In this known machine, a rotating assembly presents the individual rolls, which are accommodated in respective seatings, to a set of rotating blades. The rotating blades have a shape such as to penetrate gradually with their cutting edges into the thickness of the rolls.
These multiple severing machines are not sufficiently efficient to meet current high productivity requirements. At present, therefore, preference is given to systems which perform the cutting of the rolls in successive operations of xe2x80x9cslicingxe2x80x9d the rolls.
Moreover, the multiple-cutting machines known today are complex and bulky, and do not meet present-day safety standards.
It is an object of the present invention to provide a machine of the abovementioned type having multiple blades, with a new system for retaining the products to be cut, during cutting, which makes the machine efficient and structurally simple.
It is a further object of the present invention to provide an improved severing machine having multiple blades for the simultaneous cutting of a series of small rolls from rolls or logs of wound-up weblike material or for the cutting of other articles from elongate products, which is of simple and compact construction.
These and other objects and advantages, which will become apparent to those skilled in the art from reading the text that follows, are substantially achieved with a severing machine for elongate products, comprising, in combination:
a series of cutting blades rotating about respective axes of rotation;
a feeder rotating about an axis approximately parallel to the axes of the disk-shaped blades, having at least one peripheral seating for said products, which removes said products from a removal zone and transfers them to said blades for cutting;
a flexible member passed around at least one portion of the periphery of the rotating feeder, in order to retain the products in said at least one seating during cutting.
The rotating feeder comprises, preferably, more than one seating, more rapid operation thus being obtained. The cutting blades are, according to the preferred embodiment of the invention, disk-shaped blades, in other words having a circular cutting edge, although this is not strictly necessary. They could, for example, have a cutting edge in the form of a portion of a helix.
According to a possible embodiment of the invention, the flexible member comprises at least one continuous belt, passed around at least two return pulleys and, along a section between said two pulleys, around a portion of the peripheral development of the rotating feeder, said rotating feeder having an approximately cylindrical lateral surface along which opens said at least one seating for the products to be cut.
Further advantageous embodiments of the severing machine according to the invention are indicated in the attached dependent claims.